DIY Root Cellar Designs from 1940 Farm Bulletins

Introduction: Forgotten Farm Wisdom That Still Works

Before the advent of freezers and refrigerators, farmers relied on nature and their knowledge to keep their food fresh during long, cold winters. One of the most reliable tools they used was the root cellar—a structure built right into the earth to store potatoes, carrots, apples, onions, and other hardy crops.

In 1940, the Canadian Department of Agriculture published a bulletin explaining exactly how to build one. These plans were simple, effective, and designed for harsh prairie climates. The best part? You don’t need high-end tools or modern materials to follow them.

If you’re homesteading, living off-grid, or want a backup food storage system, these time-tested designs still work. And suppose you’re handy with a saw. In that case, this is the kind of project that fits perfectly into a weekend build, especially with a solid woodworking plan to guide you.

Want step-by-step plans for framing, shelves, and bins? Ted’s Woodworking offers over 16,000 downloadable designs—including root cellar-friendly projects perfect for DIYers.

In this post, you’ll learn the key features of a traditional root cellar, how to build one using materials you may already have, and how to adapt it for modern homestead use.

 

Why Root Cellars Still Matter Today

Most people store food in freezers and refrigerators, assuming that’s the only option. But those systems rely entirely on electricity, and once the power goes out, the clock starts ticking. Frozen meat begins to thaw. Fresh produce goes soft. And whatever’s not eaten in time ends up in the trash.

A root cellar doesn’t operate on a timer. It works because of one simple fact: underground temperatures stay relatively stable year-round. Even when surface temperatures swing from 90°F in summer to -10°F in winter, six feet underground stays somewhere between 35°F and 50°F—exactly the range you want for preserving most root vegetables.

 

Root Cellar Storage: What Works and For How Long

A properly managed cellar can store:

• Potatoes for 5–8 months
• Carrots and beets for 4–6 months
• Cabbage for 3–4 months
• Turnips, parsnips, and rutabagas for 4–5 months
• Apples (some varieties) for up to 5 months
• Squash and pumpkins (if kept dry) for 3–4 months

People used these storage times to stretch their harvest into February or March, long before refrigeration existed.

What Makes the System Work

A good root cellar does three things:

1. Regulates temperature by taking advantage of the Earth’s natural insulation
2. Maintains high humidity, which keeps produce from shriveling
3. Allows controlled ventilation, which prevents mold and rot from stale air

The result is a cold, dark, damp-but-not-wet space that mimics the storage conditions most vegetables evolved in. No plastic bags. No climate control. Just the right mix of cool air and moisture retention to keep everything firm, crisp, and edible.

Why It’s Still Relevant Today

• Power outages are common, caused by storms, blackouts, or grid failures
• Cold storage is expensive, especially off-grid or in remote areas
• Gardeners grow more than they can eat all at once
• Refrigerators remove moisture, which makes carrots go limp and potatoes sprout.

And perhaps most importantly, root cellars work quietly in the background. Once built, they don’t cost anything to run. They don’t break down. They don’t require backup generators or batteries. Suppose you can monitor the vents and make a few seasonal adjustments. In that case, you’ll have a stable storage system that can last a lifetime.

 

🛠️ Root Cellar Principles from the 1940 Bulletin (Still Relevant Today)

Before jumping into construction methods or modern upgrades, it’s worth understanding the core principles that made the original 1940 root cellar designs so effective. These weren’t arbitrary guidelines. They were the result of trial, error, and real-world performance across the harsh Canadian prairies, where winters were brutal and refrigeration didn’t exist.

Whether you’re a homesteader, a prepper, or just someone who wants reliable food storage off-grid, these principles are your foundation. We’ll break them down one by one, starting with the most fundamental: where you build, and how you control temperature.

📍 1. Location: Why Site Placement Matters More Than You Think

One of the most overlooked but critical parts of any root cellar is where you put it.

The 1940 bulletin emphasized this right up front:

“The ideal location for a root cellar is on the side of a hill.”

Farmers didn’t pick hillsides by accident. They knew it handled water runoff, kept the cold in, and made the structure last.

• Natural Drainage

Rain and snowmelt will always find the path of least resistance. By digging into a hill, you ensure water drains away from the structure, not into it. That alone can prevent mold, rot, and foundation issues without installing expensive drainage systems.

• Earth-Sheltered Stability

Hillsides insulate naturally. When you dig into a slope, the earth surrounds three walls and shields the cellar from sunlight, wind, and temperature swings. You get free thermal stability without extra materials.

• South-Facing Entrance

The bulletin advises placing your entrance on the south side if possible. Winter sun helps keep the doorway clear of snow and ice, while allowing for limited warmth during the coldest months. Just be sure to block direct light from hitting stored produce.

✅ Modern Tip:

No hill? Choose a spot with slight natural elevation and slope drainage away using gravel-filled trenches. Use a laser level or water level to verify the grade before digging.

 

🌡️ 2. Temperature: The Quiet Key to Long-Term Food Storage

Temperature control is the single biggest reason root cellars work. The idea is simple but powerful:

“Underground temperatures remain relatively stable year-round.”

At a depth of around six feet, soil becomes a natural refrigerator, staying roughly between 35°F and 50°F even as surface temps swing wildly from season to season.

• The Ideal Range

Most vegetables store best between 35°F and 40°F, where bacterial growth slows and moisture loss is minimal. Go higher, and you risk sprouting. Go lower than 28°F, and you’re risking frost damage — especially to potatoes, which don’t recover once frozen.

• Potato Healing Trick

Store freshly harvested potatoes at 60°F for the first two weeks to let bruises heal before moving them into cooler long-term storage.

• Avoiding Freeze Risk

A poorly insulated root cellar can drop below freezing in extreme conditions. That’s why insulation — especially in the roof and upper walls — is crucial. It’s not just about maintaining a cold temperature; it’s about keeping it consistent without tipping too far.

✅ Modern Tip:

Hang a basic analog thermometer just above the vegetable bins and check it weekly. If temps drop too low, you can temporarily close vents or — in extreme cases — use a kerosene lantern or heat source to bump the temp by a few degrees, just like farmers did in the 1940s.

💧 3. Humidity: Get It Right or Watch Your Food Rot

Humidity plays a huge role in how long your stored vegetables last. Too much moisture? You get mold, rot, and slimy walls. Too little? Your carrots shrivel, your potatoes wrinkle, and everything loses its crispness.

The 1940 bulletin doesn’t throw out vague advice—it points to a “fairly high degree of humidity,” but not so high that moisture condenses on the walls or ceiling. That’s your line in the sand: keep things moist, but not dripping.

• Why Humidity Matters

Root vegetables—especially carrots, beets, turnips, and parsnips—need moisture in the air to stay plump. These crops evolved underground, surrounded by damp earth. When stored in dry air (like inside a refrigerator), they lose water and shrivel up fast.

But if you overdo it, and moisture starts clinging to the walls or ceiling, you’re asking for rot. It’s a fine line, but manageable.

• How to Monitor Humidity (Without Guessing)

Use a hygrometer.

A hygrometer is a small, inexpensive tool that measures the relative humidity (RH) in the air—basically, how damp the air is inside your cellar. You can buy an analog version for under $10 or a digital one for $15–20. Mount it on the wall near your vegetable bins and check it regularly, especially when seasons change.

• Ideal range: Aim for 85–95% humidity for root vegetables
• If it drops below 80%, vegetables start drying out
• If moisture appears on the ceiling or walls, you’re over 100% saturation—fix it fast

• How to Adjust Humidity

• Too Dry? Place a shallow pan or open bucket of water inside the cellar. The water will slowly evaporate and raise humidity. You can also dampen the floor with a bit of clean water or store wet sand in trays under your bins.
• Too Damp? Improve airflow. Open the doors briefly during cool, dry mornings. Add ventilation if needed (more on that below). Avoid sealing the space too tightly unless you’re in a deep freeze.

🌬️ 4. Ventilation: The Invisible Lifeline of Your Root Cellar

Airflow might sound like a minor detail, but it’s one of the most essential parts of a functional root cellar. Without it, moisture builds up, stale air sits, and mold takes over. Good ventilation doesn’t just keep the air fresh — it keeps your food from rotting.

The 1940 farm bulletin treats this as a core feature, not an afterthought. It recommends a simple but effective system:

“One of the most common practices is to have the air drawn in at one end and out the other using intake and outlet ventilator stacks.”

This design works on a fundamental principle: cold air sinks, warm air rises.

• How the Vent System Works

A proper root cellar uses two vents:

• Air intake: runs from outside to just above the floor level inside the cellar
• Air outlet: starts near the ceiling and vents out the roof

Here’s what happens:

• Cool air enters near the floor through the intake pipe
• As the air warms slightly (from the earth or stored food), it rises
• Warm, moist air exits through the outlet vent at the top

This setup creates a natural convection loop that keeps air moving without any fans or electricity.

• How to Build and Place Vents

The original plans recommend 12-inch square ducts for a 10×14 root cellar. Still, you can also use round duct pipe (8–10 inches in diameter works for most small-to-mid-sized builds). Place the intake at the front of the cellar (usually near the door), and the outlet on the opposite end, rising at least 5 feet above the roof insulation to promote airflow.

For modern DIYers, PVC pipe with vent caps works well, and you can use adjustable flaps or simple dampers to control flow.

• Seasonal Adjustments Matter

Ventilation isn’t set-it-and-forget-it. You’ll need to adjust it based on the season:

• Fall/Early Winter: Open vents entirely to remove harvest heat and bring in cool, dry air
• Mid-Winter: Partially or fully close vents during extreme cold to prevent freezing
• Spring: Open vents at night when it’s cooler and close during the day to maintain low temperatures inside

✅ Practical Tips:

• Check your vents regularly. Clear away snow, leaves, or nests blocking the openings
• Add a rodent screen over both vents using ¼” hardware cloth
• Use a smoke stick or incense to test airflow direction on still days
• If air isn’t moving, your outlet vent may not be tall enough or may need insulation around it to maintain the draft

 

🌬️🧰 How to Build Ventilation Ducts for a Root Cellar (No Experience Needed)

A root cellar needs two vents:

1. An intake vent — to bring cool air in near the floor
2. An exhaust vent — to let warm, stale air out through the roof

You can build these with basic materials from a hardware store — no fancy tools or skills required.

🧱 Option 1: Old-School Method (Based on 1940 Plans)

If you want to stay close to the 1940 design, here’s how they did it:

Materials:

• Two wooden shafts (about 12 inches wide and square)
• Boards (1×12 or scrap lumber)
• Nails or screws
• Saw (handsaw or circular)
• Hammer or drill
• Roofing tar paper (optional)
• Hinged flap or sliding board to control airflow

 

Instructions:

1. Build a Box Shaft:
2. Nail four boards together to create a tall, hollow box—this becomes your duct.
3. Position the Vents:

1. • Intake shaft: Place this at the front corner of the cellar. Extend it from just above the floor inside to outside at ground level.

1. • Exhaust shaft: Place this at the back of the ceiling area and run it up through the roof. It should stick out at least 5 feet above the roof to encourage draft.

1. Seal the Seams:
2. If using rough lumber, staple roofing tar paper around the outside to block air leaks and moisture.
3. Control the Airflow:
4. Install a wooden flap or sliding cover over each vent so you can partially or fully close them in winter.

 

🧰 Option 2: Easier Modern Method (PVC Pipe)

This version is simpler, cheaper, and uses materials from any Home Depot or Lowe’s.

Materials:

• 8″ or 10″ diameter PVC pipe (10–15 feet total)
• Two 90° elbows
• Two vent caps or rain hoods
• Hardware cloth (¼” metal mesh to block rodents)
• Zip ties or hose clamps
• Handsaw or PVC cutter
• Expanding foam (for sealing gaps)

Instructions:

1. Measure and Cut the Pipe:

1. • For the intake, cut a length of pipe that enters the front wall near the floor, curves with a 90° elbow, and sticks up outside about 2–3 feet above ground.

1. • For the exhaust, start at the back ceiling of the cellar and run a pipe up through the roof, extending 5 feet above the roofline. Use a 90° elbow if needed.

1. Install the Pipes:

1. • Cut holes into your framing or wall where the pipes go in.

1. • Slide the pipes into place — intake near the floor, exhaust near the ceiling.

1. Secure the Openings:

1. • Cover each open end with hardware cloth to keep out rodents.

1. • Add vent caps or elbow fittings to shield from rain or snow.

1. Seal the Gaps:

1. • Use spray foam insulation around the pipe where it passes through walls or the roof to block drafts and keep things tight.

1. Optional: Add Dampers
2. You can buy inline duct dampers that slide inside the pipe and let you open/close airflow with a handle. Or use a sock, rag, or simple wood plug if you need to block airflow in extreme cold.

🔧 Tools You’ll Need (Basic)

• Handsaw (or PVC cutter)
• Screwdriver or drill
• Tape measure
• Staple gun (for old-school vent shaft)
• Spray foam (for sealing gaps)\

 

How to Build a Root Cellar (Using 1940 Plans that Still Hold Up)

Now that you understand the principles — location, temperature, humidity, and airflow — let’s get into the structure itself.

The 1940 Canadian bulletin lays out a cellar design that hits the sweet spot between simple and effective. It’s not fancy, and it doesn’t require professional tools or materials. You can build it with basic lumber, dirt, straw, and some sweat equity.

Let’s walk through the design:

📐 Basic Layout

• Size: 10 feet wide by 14 feet long
• Depth: Dug 6 feet into the ground
• Entry: A double-door vestibule creates an air buffer to reduce temperature swings
• Structure: Pole-and-beam frame (or dimensional lumber if available)
• Insulation: Thick layers of straw and soil packed over the roof and walls
• Interior: Slatted bins for storage, with a center walkway

Farmers across Saskatchewan built this layout to survive brutal winters without relying on electricity or powered ventilation.

🕳️ Digging the Pit

Start by excavating a 10×14 rectangle at least 6 feet deep. Keep the soil you remove—you’ll reuse it for insulating the roof.

If you have access to a slip scraper, it’ll speed things up. Otherwise, dig manually and ensure your walls stay square. Flatten the floor so bins can sit level.

 

🪵 Framing the Walls and Roof

Use 6″ or 8″ round poles, or cut 8×8 posts if you’re working with lumber. Here’s the basic setup:

• Ten 7-foot upright posts for the long walls
• Eight 6-foot posts for the shorter ends
• Two 18-foot ridge poles to span the ceiling
• Two 14-foot plate poles to run along the walls

Set each post on a flat stone or wood plank to prevent sinking. Brace them well. Lay the ridge poles into notches cut into the tops of the posts, and secure them firmly.

🌾 Wall Insulation

The walls must block frost, especially near the edges. Use chicken wire or page wire stapled to the inside of the posts. Then pack chaffy straw (loose, fluffy straw) tightly between the wire and the earth wall.

Packing the straw tightly creates an 8-inch insulation layer that effectively keeps out frost without incurring significant costs.

🧺 Interior Bins

Build simple bins with gaps between the boards. The gaps allow air to move between crates and keep stored produce from sweating. Add slatted floors if you can — they boost airflow under the vegetables, especially helpful for potatoes and turnips.

Leave a central walkway between bins for easy access.

 

Slatted floors are floors made with wooden boards spaced slightly apart instead of being solid. The gaps between the boards allow air to flow underneath stored produce, which helps prevent moisture buildup and rot.

🏠 Roofing the Right Way

The roof must both insulate and support a significant amount of weight.

1. Lay heavy roof boards or tightly packed poles across the beams.
2. Staple down tar paper as a moisture barrier.
3. Add alternating layers of straw and soil:

1. • Straw layers: 6″ thick (compressed)

1. • Soil layers: 8″–12″ thick

1. • Total: Build up to at least 3½ feet of insulation on top

Extend this insulation past the sides of the cellar to prevent frost from creeping in at the edges.

At ground level, dig a shallow trough filled with straw where the straw layer meets the soil. The insulation helps break the frost line and protect the interior during cold snaps.

🚪 The Double Door Vestibule

You need two doors, at least 4 feet apart, forming a small entry chamber. The vestibule holds warm air inside during winter and blocks sudden blasts of hot or cold air from entering.

Build both doors tight-fitting and well-insulated. A vestibule might not seem essential, but in freezing climates, it makes a huge difference.

✅ Modern Tip

Mount a digital thermometer and a moisture meter inside the cellar. These tools help you fine-tune your conditions and catch problems early.

• A digital thermometer with a max/min memory lets you track temperature swings.
• A moisture meter (look for one labeled “hygrometer”) shows you how damp the air is—ideally, you want 85–95% relative humidity for most root crops.

 

What Does “4 Feet Apart” Mean for Vestibule Doors?

In the root cellar plans, the double-door vestibule isn’t two side-by-side doors like in a closet. It refers to two separate doors spaced 4 feet apart, one after the other, forming a short entry hallway or buffer zone, like an airlock.

Think of it like this:

1. You open the outer door, step inside a small enclosed space (about 4 feet long)
2. Then you close the outer door behind you
3. Now, you open the inner door to enter the root cellar itself

This 4-foot space between doors is called the vestibule, and it serves a few critical purposes:

🧊 1. Temperature Control

This air buffer prevents sudden blasts of warm or cold air from rushing into the cellar. In winter, it keeps freezing air from dropping the inside temperature too fast. In summer, it keeps hot air from getting in when you open the door.

It’s the same reason greenhouses or walk-in freezers often have double doors.

🌬️ 2. Moisture and Humidity Stability

When you open a single door directly into the cellar, you lose a burst of humidity or draw in dry air. Over time, that adds up and affects the quality of your stored produce. The vestibule helps trap moisture and maintain more consistent interior conditions.

🧱 3. Structural Simplicity

You don’t need fancy framing to do this. Just:

• Frame a short enclosed corridor (about 4 feet long) in front of your cellar
• Add one door on the outside and one on the inside
• Insulate both doors as best you can — even heavy curtains or blankets can help in a pinch

If you’re building on a tight budget, this vestibule can be as basic as an overbuilt shed-style entryway with straw bales stacked around it.

 

How Woodworkers Can Build One (Using Real Plans)

You don’t need a contractor or a backhoe to build this kind of root cellar. If you know how to swing a hammer, measure twice, and follow basic plans, you can do most of the work yourself, especially the woodworking parts.

Building a root cellar is an ideal project if you’re:

• Living off-grid or looking to store food without power
• Homesteading and growing more than your fridge can handle
• Prepping for outages, inflation, or long winters
• Trying to make use of surplus produce instead of letting it rot in crates

You can build everything above ground — and most of the interior — using standard tools and a clear woodworking plan, even if you hire out the digging.

🪵 What You’ll Need to Build (and Where to Find the Plans)

Most of the wood components break down into manageable weekend projects — no guesswork needed if you follow a guide.

1. Shelving and Storage Bins

Don’t pile produce on the floor. Build slatted bins with airflow gaps to store carrots, potatoes, and apples properly. You can also use adjustable shelves for canned goods or squash. Look for bin designs that use spaced horizontal boards, and make sure the bottom allows air movement, too.

2. Framed Entryway and Vestibule

The entryway is where woodworking makes the most significant difference. A well-built vestibule frame with double doors keeps your cellar from becoming an icebox in winter or a sweatbox in summer. Use pressure-treated lumber or rot-resistant wood, and insulate the walls with rigid foam or straw bales.

3. Pole Roof Frame and Trusses

Whether you go with ridge poles and plate beams or a modern truss-style frame, the roof needs to support hundreds of pounds of insulation. The structure isn’t a garden shed roof — it’s carrying soil, straw, snow, and time. You can use pole framing (like in the 1940 plans) or cut your trusses based on roof load specs.

4. Optional Add-Ons

Depending on your setup, you might also want to:

• Frame a basic stairwell or sloped entry path
• Build a custom cellar door or hatch
• Add tool racks or pantry-style shelving inside

If you want to get fancy, some plans include integrated cold storage lockers or ventilation shafts with built-in dampers.

✅ Want the Plans Without Guesswork?

📦 Callout Box:

Want done-for-you plans for rustic shelving, underground storage, or off-grid structures?

Click here to access Ted’s Woodworking and get over 16,000 step-by-step guides, including plenty that match root cellar layouts, bin systems, doors, and small farm builds.

 

Modern Add-Ons That Make the Root Cellar Even Better

The original 1940 design works. But if you’re building today, you’ve got access to a few low-cost upgrades that make it even more reliable and easier to manage, especially if you’re living off-grid or want less day-to-day maintenance.

Here’s how to take a proven build and bring it into the 21st century without ruining the simplicity.

☀️ 1. Add a Solar-Powered Vent Fan

Natural airflow is usually enough, but some sites have still air or poor circulation. That’s where a small solar fan comes in.

• Mount it near the exhaust vent to help pull warm, stale air out
• Use a simple 12V panel and fan kit (often under $50)
• No batteries needed — it runs only when the sun’s out, which is when you most need airflow anyway

A solar vent fan provides your cellar with a ventilation boost on hot days without relying on the grid.

🐭 2. Install Rodent Screens on All Vents

Open vents are an invitation to mice, squirrels, and other animals seeking warmth or food.

• Cut squares of ¼-inch hardware cloth (galvanized steel mesh)
• Attach them securely to both ends of the intake and exhaust vents using hose clamps, screws, or metal zip ties
• Check them seasonally to clear debris

Don’t skip this — rodents will chew through stored food, nest in straw insulation, and damage your bins.

🌧️ 3. Add a Waterproof Barrier Under the Roof Insulation

The 1940 plans use tar paper between the roof boards and the insulation. You can still do that — or go one better.

• Use heavy-duty roofing underlayment or a rubber pond liner
• Lay it over the roof decking before adding straw and soil
• Proper waterproofing prevents water from soaking through and dripping onto your stored vegetables

It’s one of the cheapest ways to protect the integrity of your entire setup.

💡 4. Mount a Battery-Powered Motion Light

You won’t run power underground, and lanterns can be a fire hazard. The simplest fix? Stick-on LED motion lights.

• Use battery-powered puck lights with motion sensors
• Mount one near the entrance and another near your bins
• Many models run for months on a single set of AA batteries

No wires, no switches — just light when you need it.

 

🧱 Conclusion: Old Plans, Real Value

You don’t need a degree in engineering—or a big budget—to build something that works. These root cellar designs came from farmers who needed real results using the tools and materials they had. And they got it right.

The beauty of this system is its simplicity: dig deep, insulate well, ventilate smart, and let the earth do the rest. No wires. No motors. No monthly electric bill.

Today’s homesteaders, preppers, and off-grid DIYers can take these 1940 blueprints and make them even better with a few smart upgrades. But the core idea still holds: if you store food the way nature intended, it lasts longer, costs less, and survives power outages without a problem.

🛠️ Ready to Start Building?

You don’t need to reinvent the wheel — follow proven plans.

And if you want help building out your root cellar, shelves, or farmstead toolshed,

👉 Ted’s Woodworking can help you get started today with 16,000+ guides and blueprints.